Automobile injury trends in the contemporary fleet: Belted occupants in frontal collisions

<b>Objective:</b> As vehicle safety technologies and evaluation procedures advance, it is pertinent to periodically evaluate injury trends to identify continuing and emerging priorities for intervention. This study examined detailed injury distributions and injury risk trends in belted occupants in frontal automobile collisions (10 o’clock to 2 o’clock) using NASS-CDS (1998–2015). <b>Methods:</b> Injury distributions were examined by occupant age and vehicle model year (stratified at pre- and post-2009). Logistic regression models were developed to examine the effects of various factors on injury risk (by body region), controlling for delta-V, sex, age, height, body mass index (BMI), vehicle model year (again stratified at 2009). <b>Results:</b> Among other observations, these analyses indicate that newer model year vehicles (model year [MY] 2009 and later) carry less risk of Abbreviated Injury Scale (AIS) 2+ and AIS 3+ injury compared to older model year vehicles, with odds ratios of 0.69 (AIS 2+) and 0.45 (AIS 3+). The largest reductions in risk between newer model year vehicles and older model year vehicles occur in the lower extremities and in the risk of skull fracture. There is no statistically significant change in risk of AIS 3+ rib fracture or sternum injury between model year categories. Females are at greater risk of AIS 2+ and AIS 3+ injury compared to males, with increased risk across most injury types. <b>Conclusions:</b> For belted occupants in frontal collisions, substantial reductions in injury risk have been realized in many body regions in recent years. Risk reduction in the thorax has lagged other body regions, resulting in increasing prevalence among skeletal injuries in newer model year vehicles (especially in the elderly). Injuries also remain common in the arm and hand/wrist for all age ranges studied. These results provide insight into where advances in the field have made gains in occupant protection and what injury types remain to be addressed.

<b>研究目标：</b> 随着车辆安全技术与评估规程的持续发展，定期评估损伤趋势以识别持续存在与新出现的干预优先级具备重要现实意义。本研究采用1998-2015年的美国国家汽车采样系统碰撞数据系统（NASS-CDS）数据集，对正面汽车碰撞（碰撞方位为10点钟至2点钟）中使用安全带的乘员的详细损伤分布与损伤风险趋势展开分析。<b>研究方法：</b> 本研究首先按乘员年龄与车辆生产年份（以2009年为界分为前后两个层级）对损伤分布进行分析。随后构建逻辑回归模型，在控制碰撞速度变化量（delta-V）、性别、年龄、身高、身体质量指数（Body Mass Index）、车辆生产年份（仍以2009年为界进行分层）等变量的前提下，探究各类因素对不同身体区域损伤风险的影响。<b>研究结果：</b> 除其他观测结论外，本次分析显示，与老旧车型相比，2009年及之后生产的新款车型（车辆生产年份[MY] 2009及以后）中乘员的简略损伤量表（Abbreviated Injury Scale）2级及以上、3级及以上损伤风险更低，其优势比分别为0.69（AIS 2+）与0.45（AIS 3+）。新款车型相较于老旧车型，损伤风险降幅最大的区域为下肢，以及颅骨骨折风险。不同车辆生产年份组别之间，AIS 3级肋骨骨折或胸骨损伤的风险未出现统计学意义上的显著变化。女性乘员相较于男性，出现AIS 2+与AIS 3+损伤的风险更高，且在多数损伤类型中均表现出风险升高的特征。<b>研究结论：</b> 对于正面碰撞中使用安全带的乘员而言，近年来多个身体区域的损伤风险已得到显著降低。但胸部区域的损伤风险改善幅度落后于其他身体区域，导致新款车型中（尤其老年乘员）骨骼损伤的占比有所上升。此外，所有被研究年龄层的乘员仍普遍存在手臂、手部/腕部损伤。本次研究结果可为车辆乘员保护领域的技术进步已取得的成效，以及仍需解决的损伤类型提供参考依据。